Once Upon a Time in London is a 2019 British crime drama film directed by Simon Rumley, written by Will Gilbey, Rumley and Terry Stone, and starring Leo Gregory, Terry Stone, Holly Earl, Dominic Keating, Geoff Bell and Jamie Foreman. The film is about the notorious London gangsters Billy Hill and Jack Comer.

Simon Rumley is a British screenwriter, director and author. Mostly associated with the horror genre, he was described by Screen International as "one of the great British cinematic outsiders, a gifted director with the know-how to puncture the conventions". He has won several awards and worked with, among others, Roger Lloyd-Pack, Greta Scacchi, Noah Taylor and Peter Facinelli.